Currently, the use of a Bluetooth function is high due to rapid spread of a smartphone and the increased use of Bluetooth. The Bluetooth function can be used inside a vehicle because to make a call or listen music while driving the vehicle.
However, connection between the vehicle and the smartphone is not automatically established for the next use even though the connection was made in the past because connection information of the smartphone registered in a head unit of the vehicle providing a Bluetooth function is deleted, or connection information with the vehicle is deleted from the smartphone. For example, when some people (e.g., family members) share a vehicle and one of them deletes information about a registered device by mistake, or when information about a head unit is deleted from a Bluetooth list of the smartphone due to a malfunction caused during the operating system of the smartphone is frequently upgraded. Particularly, since a pairing procedure may be complicated, a user who is not familiar with the Bluetooth function, may not establish Bluetooth connection due to deletion of a connection list.